A connection between an electronic device and a substrate may be achieved using an anisotropic conducting film (ACF). Conductive bumps are formed on the electronic device. The locations of the conductive bumps correspond to contact pads on the substrate. An ACF is placed between the electronic device and the substrate. By applying pressure, a connection is made between the electronic device and the substrate.
An ACF has conducting spheres suspended throughout a deformable film. When pressure is applied in one direction between connection points on opposite sides of the film, the spheres contact each other and the connection points, creating a conductive path. Because pressure is applied in one direction, spheres in an orthogonal direction may not contact each other. Thus, a conductive path is formed between opposite sides of the film, but not between adjacent connection points on one side of the film.
However, because the conducting spheres are distributed throughout an ACF, as the pitch of the connection points connected using the ACF is reduced, the likelihood of spheres contacting each other in a direction orthogonal to the direction of the applied pressure increases. Thus, ACF has an inherent limitation on the lateral spacing of connection points.